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1 | /* java.lang.VMThrowable -- VM support methods for Throwable. |
2 | Copyright (C) 1998, 1999, 2002 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GNU Classpath. | |
5 | ||
6 | GNU Classpath is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU Classpath is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU Classpath; see the file COPYING. If not, write to the | |
18 | Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
19 | 02111-1307 USA. | |
20 | ||
21 | Linking this library statically or dynamically with other modules is | |
22 | making a combined work based on this library. Thus, the terms and | |
23 | conditions of the GNU General Public License cover the whole | |
24 | combination. | |
25 | ||
26 | As a special exception, the copyright holders of this library give you | |
27 | permission to link this library with independent modules to produce an | |
28 | executable, regardless of the license terms of these independent | |
29 | modules, and to copy and distribute the resulting executable under | |
30 | terms of your choice, provided that you also meet, for each linked | |
31 | independent module, the terms and conditions of the license of that | |
32 | module. An independent module is a module which is not derived from | |
33 | or based on this library. If you modify this library, you may extend | |
34 | this exception to your version of the library, but you are not | |
35 | obligated to do so. If you do not wish to do so, delete this | |
36 | exception statement from your version. */ | |
37 | ||
38 | package java.lang; | |
39 | ||
40 | import gnu.gcj.runtime.NameFinder; | |
421f9e60 | 41 | import gnu.gcj.runtime.StackTrace; |
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42 | |
43 | /** | |
421f9e60 | 44 | * VM dependent state and support methods Throwable. |
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45 | * It is deliberately package local and final and should only be accessed |
46 | * by the Throwable class. | |
47 | * <p> | |
48 | * This is the version used by libgcj (http://gcc.gnu.org/java/). | |
49 | * | |
50 | * @author Mark Wielaard (mark@klomp.org) | |
51 | */ | |
52 | final class VMThrowable | |
53 | { | |
421f9e60 | 54 | private gnu.gcj.runtime.StackTrace trace; |
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55 | |
56 | /** | |
57 | * Private contructor, create VMThrowables with fillInStackTrace(); | |
58 | */ | |
59 | private VMThrowable() { } | |
60 | ||
61 | /** | |
62 | * Fill in the stack trace with the current execution stack. | |
63 | * Called by <code>Throwable.fillInStackTrace()</code> to get the state of | |
64 | * the VM. Can return null when the VM does not support caputing the VM | |
65 | * execution state. | |
66 | * | |
67 | * @return a new VMThrowable containing the current execution stack trace. | |
68 | * @see Throwable#fillInStackTrace() | |
69 | */ | |
421f9e60 AH |
70 | static VMThrowable fillInStackTrace(Throwable t) |
71 | { | |
72 | VMThrowable state = null; | |
73 | ||
74 | /* FIXME: size of the stack trace is limited to 128 elements. | |
75 | It's undoubtedly sensible to limit the stack trace, but 128 is | |
76 | rather arbitrary. It may be better to configure this. */ | |
77 | if (trace_enabled) | |
78 | { | |
79 | state = new VMThrowable (); | |
80 | state.trace = new gnu.gcj.runtime.StackTrace(128); | |
81 | } | |
82 | return state; | |
83 | } | |
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84 | |
85 | /** | |
86 | * Returns an <code>StackTraceElement</code> array based on the execution | |
87 | * state of the VM as captured by <code>fillInStackTrace</code>. | |
88 | * Called by <code>Throwable.getStackTrace()</code>. | |
89 | * | |
90 | * @return a non-null but possible zero length array of StackTraceElement. | |
91 | * @see Throwable#getStackTrace() | |
92 | */ | |
93 | StackTraceElement[] getStackTrace(Throwable t) | |
94 | { | |
95 | StackTraceElement[] result; | |
421f9e60 | 96 | if (trace != null) |
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97 | { |
98 | NameFinder nameFinder = new NameFinder(); | |
421f9e60 AH |
99 | result = nameFinder.lookup(t, trace.stackTraceAddrs(), |
100 | trace.length()); | |
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101 | nameFinder.close(); |
102 | } | |
103 | else | |
104 | result = new StackTraceElement[0]; | |
105 | ||
106 | return result; | |
107 | } | |
108 | ||
109 | // Setting this flag to false prevents fillInStackTrace() from running. | |
110 | static boolean trace_enabled = true; | |
111 | } |